Recently ive been working on my video game collection and have been trying to pickup as many games as I can at low prices. Pretty much I will find a lot of games and break apart the lot into specific titles. The key is finding decent deals at this time because people use ebay and know what various video games are worth. Reselling is an information game mostly and those who know what something is worth will ultimately be the winners.
Like I said the hardest part is finding places to buy used games. I live in an area that is heavily picked so garage sales are mostly a bust for me, but they might be worth it for you. Also garage sales have the added benefit of having other items to potentially make money on if you know what to look for. Blurays and dvds that are rarer are things to look out for. I have found that Disney stuff is really the most sought after, so if you can pick them up for 50 cents, it might be worth the gamble.
The strategy I use the most, which has worked well for me in the past couple of months has been visiting various thrift and donation stores in my area that sell things for a flat fee. Note that goodwill is usually bad for this because they check ebay and price their items accordingly. Only the low price stuff at goodwill is actually priced at a flat fee and you wont make any profit. What you do is leave your number and tell them that you will buy any video game stuff that comes in. Usually when people donate, they throw in 5-10 games and most of the time, one or two will pay for the whole lot.
I have three to four stores in my area that now call me whenever new stuff comes in and I go and pick it up. Half of the time its junk that I will just list on ebay, but the other half I will get gems that I didnt have in my collection. Sometimes one trade in will make it worth the whole process. I had $200 of ps1 games donated and I purchased them for $10. There is no greater feeling than hitting the video game lottery. Selling on ebay is another matter all together, but I will write another article for that in the future, its not as hard as people think.
For some reason people dont believe that old video games are worth anything which means that you have an advantage when buying them. Many of the old ways (flea markets, garage sales, craigslist, ect) are so over hunted at this point that it is very hard to even find a single great deal. The key is to get creative and not be afraid to ask stores directly and give them your number. There are also other ways like running an ad in the local paper, which works well if you are trying to buy in bulk. Let me know if you have any other ideas.